Science in the Classroom is a collection of annotated research papers and accompanying teaching materials designed to help students understand the structure and workings of professional scientific research.

Materials

Purpose

To help students identify the various natural resources used to produce common items; to understand how people use science and technology to produce those items.

Context

This lesson is the first of a two-part series on garbage and recycling. These lessons are meant to help students develop an understanding of what many of the common items we use every day are made and how recycling can help reduce waste.

Garbage 1: The Roots of Trash invites students to take a closer look at the everyday items they throw in the trash. Students are prompted think about what everyday products—such as bottles, cans, cartons, plastic, and food—are made of and how they are generally produced. They learn about natural resources, both renewable and nonrenewable, and work in teams to further research and report on how these resources and products are developed and used up before being discarded in the trash.

In Garbage 2: Recycling, students apply what they have learned about throwaway products—and the valuable natural resources from which they’re derived—by thinking about where garbage goes after they throw it out. They also examine their own ideas and habits about recycling and discover what a serious effect litter and mass waste disposal have on the environment. They should come to realize that recycling is one solution to limit this ongoing global problem. They learn about how recycling generally works, what kinds of products can be recycled, and what other valuable products recycled materials can be turned into.

Young children should be given opportunities to study and manipulate many different kinds of materials, from clay and paper to metals and plastics. This allows them to begin learning about the properties that make up materials as well as about manufacturing. This may also include identifying material properties and figuring out their suitability for different purposes. It is not too early for children to begin to wonder what happens to something after it has been thrown away. By the time they reach the 3-5 grade level, students should already understand that some kinds of materials are better than others for making any particular thing, that several steps are usually involved in making things, and that some materials can be used over again. Working with products and investigating their base properties can help students discover the properties of various materials and begin to identify how people transform materials into useful objects. (Benchmarks for Science Literacy, pp. 187–188.)

It will be helpful if students begin to see that advancements in technology over the years have led manufacturers to use some natural resources much more rapidly than they can be replenished. (This includes both renewable and nonrenewable resources, which they will learn about in this series.) Many forests worldwide, for example, have been gradually reduced, and ore deposits are being depleted. These kinds of threats to the environment have prompted the search for substitute materials and new methods and technology to recycle resources that can be renewed. Nevertheless, given the overwhelming demand for manufactured goods globally—and the tons of trash it produces—the future welfare of the planet will depend heavily on how we develop, use, and restrict technology and our consumption habits. (Science for All Americans, pp. 107, 111–112.) It is important to impress upon students at this early stage that one of the best ways for them to protect the environment is to make recycling a natural part of their everyday lives. Every plastic bottle, newspaper, or bag of garbage counts.

While teaching, also keep in mind that research on student understanding of materials suggests that the tasks of classifying objects according to what they are made of and of comparing properties of materials can be challenging for early elementary-school children. In addition, elementary-school children may have limited knowledge or hold misconceptions about the origins and transformations of materials. (Benchmarks for Science Literacy, p. 349.)

Motivation

Begin the lesson by quietly walking over to the classroom trash bin. Grab students' attention and interest by rummaging around in the bin as if you're looking for something. Then pull out the plastic bag you placed there before teaching this lesson. Next, ask students:

What is this? (holding up the bag)

Once they recognize that it's trash, dump the contents of the bag on your desk and have the class identify the soda can, milk carton, glass bottle, beef product, and plastic bag itself. Continue the investigation by asking:

Where do you think this trash came from?

What kinds of things do you throw away?

What kinds of things are in the garbage in your home?

Where do you put your trash? (Note: Encourage students to think about different kinds of trash by asking about the different places they put their trash—bathroom wastebasket, kitchen garbage, recycling bin, etc.)

(Accept all reasonable answers. Encourage students to elaborate on their responses.)

Next, distribute the What Things Are Made Of student sheet. After looking over the sheet and explaining the directions, encourage students to walk around the classroom or school looking for items that interest them. (They can look anywhere—in garbage cans, on desks, or in their book sacks.) As directed, in the first column they should list items whose composition they know and in the second column, items whose origins they are less certain (and about which they would like to learn more).

When students are finished exploring and filling out their sheets, take time to discuss and compare their findings. On the blackboard, list several correct examples from each of the two categories. Help students come up with information on the composition of items they wonder about, such as how pencils are made from wood and lead.

Make a point to include in this discussion each of the items from your trash bag (plastic bag, milk carton, soda can, glass bottle, beef item) to help prepare students for a discussion of different kinds of natural resources and a research activity in the Development section.

Development

Use the discussion of students' findings as a basis for introducing and talking about the concepts of natural resources (useful materials from the earth, such as coal, oil, natural gas, and trees), renewable resources (resources that can be replenished at approximately the same rate at which they are used), and nonrenewable resources (resources that become depleted more quickly than they naturally regenerate). This can be done by asking questions such as these:

What are natural resources?

What are renewable resources? (What do you think renewable means?)

What are nonrenewable resources? (What do you think nonrenewable means?)

Which of these resources on the blackboard do you think are _________ (natural/renewable/nonrenewable resources)?

Once students have a working understanding of what renewable and nonrenewable resources are (and how they differ), erase the board and list these five resource categories: animals, fossil fuels, metals, plants/trees, and sand. (Inform students that fossil fuels are deposits in the earth that are used as fuel, such as coal, petroleum, and natural gas.) For each of the five categories, ask this question:

Do you think this resource is renewable or nonrenewable? Why?

Help students see that animals, plants/trees, and sand are renewable resources, while many fossil fuels and metals are nonrenewable.

Then help students to think of examples of items in each of these categories. Include items from the trash bag. (Note: Students may have trouble naming products in the fossil fuels and sand categories. Examples of products made from fossil fuels include trash bags, tires, clothing, plastic containers, and luggage. Common products made from sand include glass bottles, mirrors, windows, concrete, and paint.)

Questions that might emerge from this discussion may include, "How do they turn sand into bottles?" or "How are tires made from fossil fuels?" Explain that students will have a chance to find the answers themselves in an upcoming activity. To help prepare them for the activity, ask questions such as:

How do you think animal meat is turned into a hot dog?

Where does animal meat generally come from?

Where do you think hot dogs are made?

What kinds of things are needed to make hot dogs?

What kinds of people do you think are involved in turning meat into hot dogs?

This should help students begin to recognize the large role that science and technology (transportation, machinery, packaging, computerization, etc.) play in turning natural resources into products that we use every day. Have them consider a few other examples, such as how paper is turned into napkins or how concrete is made from sand, before they begin the research activity that follows.

Divide the class into five teams. Assign each team a piece of trash from your desk. These five products and the natural resources from which they are made are:

Plastic bag—fossil fuels

Milk carton—paper/trees

Soda can—metals

Glass bottle—sand

Meat item (beef)—animals

Distribute the Roots of Trash student sheet to each team member. Point out the separate Product and Natural Resource categories and read over the questions to help students understand the objective.

Note: Select the questions for students to answer based on their level and abilities.

Inform students that they will need to work together using library resources and the Internet to find information about the trashed product and the natural resource that was used to manufacture it. (Encourage students to ask the librarian for assistance in their searches.) Students may also use the Internet resources listed on the Roots of Trash student esheet (and listed below) for facts and background information on their topics.

Assessment

Once all teams have completed their student sheets, have them present their findings to the class. Encourage an open class discussion of each of these typical throwaway products and the natural resources that are used to produce them.

As a way to review what students have learned and prepare them for the second lesson, ask questions such as these:

Before this lesson, did you ever think about the things you threw away? Why or why not?

Do you think people should think about these kinds of things? Why or why not?

What did you find most interesting about the products or natural resources you researched? Why?

Are you surprised by all the technology that is involved in turning natural resources into everyday products?

What if we didn't have science and technology? Would we have tires? Glass bottles? What would life be like without these things?

As a way to review, reinforce, and continue to broaden their awareness about products—and the natural resources to which they can be traced—you may wish to finish the lesson by having students play Trash Bingo, found in the Tracing Trash Back to Its Roots classroom activity.

Extensions

This lesson may be supplemented by other related Science NetLinks lessons such as Paper Production, which teaches students how to make paper by hand as compared to the manufactured process used in modern plants. Energy Sources and Use can also teach students about different renewable and nonrenewable sources of energy and the advantages and disadvantages of each.

At the Rotten Truth About Garbage, students can find a number of facts, activities, and other interesting environmentally friendly resources that will help them further their understanding of garbage (solid waste in particular), where it comes from, where it goes, and all the different ways they can help to minimize waste in their lives to protect the environment.